2026 年 13 巻 p. 451-455
Spontaneous spinal epidural hematoma (SSEH) presents with back pain followed by myelopathy. Venous plexus disruption is common, and arterial bleeding is extremely rare. Here, we report a case of acute spontaneous spinal epidural hematoma that showed spot sign on computed tomographic angiography and was treated.
A 48-year-old woman with no medical history experienced unprovoked back pain and visited a local hospital, where she was placed under observation. Numbness gradually developed in both legs, and the patient visited our emergency room 5 hours after the onset of symptoms. Magnetic resonance imaging revealed spontaneous spinal epidural hematoma on the left ventrolateral side at the T4-6 level, and computed tomographic angiography showed a spot sign at T5-6. During the examination, the patient's paraplegia progressed, and she presented with bladder-rectum dysfunction. She was diagnosed with spinal shock and underwent emergency surgery 9 hours after the onset of symptoms. The hematoma was removed and the source of arterial bleeding was treated, generating a complete recovery.
In cases of acutely progressing paraplegic spontaneous spinal epidural hematoma, contrast-enhanced computed tomographic angiography is useful for identifying the source of bleeding, and in cases of arterial bleeding, emergency decompression and vascular ligation are useful.
Acute spontaneous spinal epidural hematoma (SSEH) is rare, but it is important for neurosurgeons to be aware of it because it presents with rapidly progressing spinal cord damage. A review of more than 1000 cases since SSEH was first reported indicates a bimodal onset, peaking in the 20s and 50s, with a wide range of contributing factors.1) Depending on the severity of the spinal cord injury, surgery may be the only treatment option, and the timing of the surgery significantly affects the prognosis.1)
We report a rare case of hyperacute SSEH in a healthy middle-aged woman who presented with gradual deterioration of spinal cord injury over several hours, in which contrast-enhanced magnetic resonance imaging (MRI) and computed tomography (CT) findings were useful for surgical intervention.
A 48-year-old woman with no medical history experienced unprovoked back pain and visited a local hospital, where she was placed under observation. Numbness gradually developed in both legs, and the patient visited our emergency room 5 hours after the onset of symptoms (Frankel grade D). MRI revealed hyperacute SSEH on the left ventrolateral side at the thoracic 4-6 level (Figure 1A-D), and contrast-enhanced MRI showed heterogeneous enhancement within the hematoma (Figure 1E and F). Three-dimensional CT angiography (3D-CTA) showed a spot sign at T5-6 level (Figure 1G-I). Neurological assessment after the examination showed that the manual muscle test was 2/5 in the right lower limb and 1/5 in the left lower limb, and tendon reflexes in both lower limbs were hyperactive and pathological reflexes were positive (Frankel grade B) 7 hours after the onset of symptoms. Spinal angiography was not performed owing to the worsening of neurological symptoms. CT spot signs indicated the presence of a bleeding source in the left T5-6 epidural space. The patient's paraplegia worsened; she went into spinal shock with urinary retention (Frankel grade A) and underwent emergency surgery 9 hours after the onset of symptoms.
A, B: Initial magnetic resonance imaging (MRI) T2 weighted image (WI) revealed a mixed intensity mass with intramedullary hyperintensity in the left ventrolateral region of T5-7 level. C, D: Initial MRI T1WI revealed a hyperintensity mass in the left ventrolateral region of T5-7. E, F: Contrast-enhanced MRI showed heterogeneous enhancement within the epidural hematoma (white arrow). G, H: After contrast injection computed tomography (CT) showed spot signs (yellow allow). I: Three-dimensional CT angiography showed small aneurysmal like region (yellow allow).
Under general anesthesia, a left T4-6 hemilaminectomy and a T5-6 foraminotomy were performed with the patient in the prone position. An epidural hematoma was observed on the left ventrolateral side, and a longitudinal artery was found after irrigation and aspiration removal (Figure 2A). Intraoperative indocyanine green video angiography revealed bleeding from the radiculomeningeal artery (Figure 2B). The T6 root was compressed caudally, and an aneurysmal-like hematoma was observed in the anastomotic branch extending cranially from the radiculomeningeal artery (Figure 2C). The aneurysm that was the source of the bleeding was coagulated and separated (Figure 2D). Histopathological findings showed hematoma within the no aneurysmal and vascular malformation regions (Figure 2E). Medical illustrations of intraoperative findings are shown (Figure 2F). The final diagnosis for the bleeding source in SSEH was some kind of breakdown of the radiculomeningeal artery.
A: Intraoperative findings after hematoma removal after left T4-6 hemilaminectomy revealed a longitudinal artery (black arrow) running from the caudal epidural space. B: The source of bleeding (white arrowhead) was identified using indocyanine green video-angiography. C: Intraoperative findings after hematoma removal revealed that the T6 root (black asterisk) was compressed caudally and an aneurysm (white asterisk) believed to be the source of bleeding was found in the anastomotic branch (black arrow) from the radiculomenigeal artery (double white arrows). D: The aneurysmal like region (white asterisk) that was the source of bleeding was coagulated and removed. E: Histopathological findings (Elastica van Gieson stain) showed hematoma (white asterisk) within the no aneurysmal regions. F: Illustration of intraoperative findings. T6 root (black asterisk), radiculomenigeal artery (double black arrows), anastomotic branch (double black asterisks), ruptured vessel (black arrow), hematoma (white asterisk), DM; dura matter. G, H: Postoperative MRI T2WI shows that the hematoma has been removed.
MRI: magnetic resonance imaging; T2WI: T2 weighted image
After surgery, the paraplegia was gradually relieved, and an MRI performed 2 weeks after surgery showed that the hematoma had been removed (Figure 2G and H). Rehabilitation treatment was performed, and the patient made a full recovery 3 weeks after surgery. No recurrence has been observed 1 year after surgery.
The contributing factors to SSEH are reported to be iatrogenic (e.g., coagulation disorders, spinal puncture, etc.) in 18% of cases, non-iatrogenic (e.g., trauma, pregnancy, etc.) in 29%, multifactorial in 11%, and 42% with an unknown cause.1) In patients with a short time interval since symptom onset (within 48 hours) and those with a short duration of complete neurological symptoms (within 12 hours), surgical treatment appears to yield good neurological functional recovery.2) Surgery is often required, particularly at the thoracic spinal cord level.1,3) In contrast, spontaneous recovery is frequently observed in cases when the hematoma has spread to 4 or 5 vertebral bodies or more, but the treatment method should ultimately be determined by the progression of neurological symptoms.3) Postoperative outcomes were determined by the severity of preoperative neurological defects and the use of anticoagulants, and hypertension was reported not to be a sole risk factor.4) Recent reports indicate that factors associated with a poor prognosis include thoracic spine issues, anticoagulant use, neurological severity at admission, and rapid deterioration within 6 hours.5)
Pathophysiology and diagnosis of SSEHFor 42% of SSEH cases, no known cause exists.1) The disruption of the intravertebral venous plexus has long been considered a leading theory for the formation of SSEH, a condition of unknown cause.4,6) Previous studies describe cases of spontaneous spinal hematomas with initially negative digital subtraction angiography (DSA) findings, but abnormal vascular structures found intraoperatively. Albrecht et al.7) reported that they performed DSA on 5 of 20 cases of spontaneous spinal hematoma and found vascular abnormalities in 25% of them.7) Although rare, particular attention should be paid to the underlying vascular malformations to prevent the progression and recurrence of hematomas.7)
MRI is the gold standard for the early diagnosis of spinal hematoma and is necessary for determining the stage of the hematoma and deciding on treatment.8) Liu et al.9) performed contrast-enhanced MRI on 7 out of 23 cases of SSEH and reported that various contrast enhancements were observed in the hematoma in 6 of those. Spot signs on 3D-CTA have been reported in spontaneous spinal hematoma10) and SSEH,11) making it a valuable diagnostic method in cases with time constraints. Regarding extravascular contrast agent leakage in intracranial hematomas, also known as the CT spot sign, numerous clinical studies have reported on its effects on hematoma enlargement, localization of the bleeding source vessel, and therapeutic efficacy.12) For intraspinal canal hematomas, only scattered case reports exist, and details remain unclear. However, in cases when neurological symptoms are exacerbated, this finding allows for the omission of angiography in searching for the bleeding source.10,11) Yu et al.13) performed spinal angiography in 40 out of 55 cases of SSEH and reported that epidural arteriovenous fistula was observed in 6 cases (15%). Rebleeding was observed in 8 out of 19 cases (34.5%) treated with minimally invasive therapy, suggesting the importance of preoperative DSA.13)
Location and arterial anatomy of SSEHSSEH were usually located dorsally (92.7%) into the spinal canal, and the average length was 4 segments.4) The prevalence of SSEH in the posterolateral region supports the theory of disruption of the posterior internal vertebral venous plexus. The rarity of ventral lesions suggests the involvement of arterial breeding from spinal epidural arteriovenous fistula.13) According to Madhugiri et al.,14) 44.7% were associated with an arteriovenous malformation, and 55.3% were isolated. Among all the spinal aneurysms, only 6.3% were extradural.
The anatomy of the epidural artery within the spinal canal involves the branching of the dorsal somatic, meningeal branch, and prelaminar artery from the radiculomeningeal artery along the nerve root. An anastomotic branch exists between the superior and inferior radiculomeningeal arteries. In reported cases of ventral SSEH due to retrocorporeal artery ruptured dissecting aneurysm in the dorsal somatic branch, endovascular treatment has been performed.15) Yamada et al.16) have reported an interesting case of spinal dural arterial venous fistula recurrence due to a cranial (T8) longitudinal anastomotic artery after embolization of a T9 radiculomeningeal artery.
In this case, the cause of the acute spinal epidural hematoma was presumed to be the formation and rupture of a pseudo-aneurysm of an ascending anastomotic branch branching from the T5 radiculomeningeal artery. Furthermore, it was considered that mechanical stress due to caudal compression by the hematoma led to rebleeding.
SSEH presenting with recurrent progression and worsening of spinal cord symptoms should be diagnosed by CT spot sign with arterial hemorrhage, and preparations for early surgery should be conducted.
All authors have no conflict of interest.
Informed consent was obtained from the patient.
